Periodically and aperiodically microstructured surfaces of a few micrometers to a few nanometers are used for a plurality of applications, especially electronic and optical components as well as sensors and in microtechnology. The production of such microstructured surfaces takes place by using known lithographic techniques suitably selected in accordance with the type of microstructure desired. Thus, e.g., structures in the nanometer range can be produced with electron-beam lithography and ion-beam lithography, and corresponding systems are commercially available. Furthermore, atomic-beam lithography allows large-surface periodic line patterns and different two-dimensional periodic structures to be produced by controlling the interactions of atomic beams with light masks.
However, since these methods have the disadvantage that they are not economically justifiable and/or supply no periodic structures in the nanometer range and/or can only be controlled by physical parameters and therefore require very expensive apparatuses, the so-called micellar block copolymer nanolithography was developed with which nanostructured surfaces with a periodicity in the lower nanometer range between 10 and 170 nm can be produced. The micellar block copolymer nanolithography method is described in detail in the following patents and patent applications: DE 199 52 018, DE 197 47 813, DE 297 47 815 and DE 197 47 816.
Template effects play an important part in micellar block copolymer nanolithography. This includes the setting of auxiliary structures that control the growth, structure and arrangement of the system built on them. Such templates are, e.g., block copolymers and graft copolymers that associate in suitable solvents to micellar core shell systems as well as highly branched dendritic molecules with a core shell structure. These core shell structures serve to localize inorganic precursors from which inorganic particles with a controlled size can be deposited that are spatially separated from each other by the polymeric casing. It is advantageous here that the core shell systems or micelles can be applied as highly ordered monofilms on different substrates by simple deposition procedures such as spin casting or dip coating. The organic matrix is subsequently removed without residue by a gas-plasma process or by pyrolysis as a result of which inorganic nanoparticles are fixed on the substrate in the arrangement in which they were positioned by the organic template. The size of the inorganic nanoparticles is determined by the weighed portion of a determined inorganic precursor compound and the lateral distance between the particles through the structure, especially by the molecular weight of the organic matrix. As a result, particle sizes of Au, Ag, Pt, Pd, Ni, Co, Fe and Ti particles as well as their oxides and alloys between 1 and 20 nm can be deposit in ordered patterns, the patterns having a periodicity corresponding to the spherical core shell system between 10 and 170 nm.
A prerequisite for the above-described micellar block copolymer nanolithography method is that the substrates consist of materials or material mixtures that withstand without damage the gas-plasma process or pyrolysis process for removing the organic matrix. Therefore, customarily noble metals, oxidic glasses, monocrystalline or multicrystalline substrates, semiconductors, metals with or without passivated surface, insulators or in general substrates with a high resistance to subsequent etching procedures are used as substrates. However, organic substrates and a plurality of inorganic substrates are to be excluded on account of their instability in the gas-plasma process or pyrolysis process for use in the block copolymer nanolithography method. Moreover, substrates are excluded whose surface is not level enough to permit a regular self-organization of the polymeric micelles. The coating of membranes that are a few nanometers thick can also not be realized technically with this method.
This is disadvantageous in as far as in particular organic polymeric substrates as well as the inorganic substrates that can not be used for the block copolymer nanolithography method have a great practical and economic significance for the production of, e.g., conductor paths in the manufacture of chips, in the cultivation of cells, bacteria and viruses as well as for the use as implants.
For example, work is being carried out with a large number of cells and cell cultures for practical and economical viewpoints with culture dishes consisting of plastic or special polymers. They are used, e.g., to multiply cells, differentiate cells or to generate tissue in general. However, the nanostructure was previously not able to be transferred to polymeric surfaces and therefore could not be previously used for the adjustment of adhesion-mediated cellular function.
Furthermore, the use of known substrates of metals, glasses monocrystalline or multicrystalline substrates and semiconductors has the disadvantage that they have great strength that can not be adjusted as desired. However, there is a demand for structured surfaces that are soft and flexible and can be applied, e.g., in the form of a foil on objects such as implants or stent materials and thus can provide these objects with a structured surface. Furthermore, the strength of the surfaces plays a part for the differentiation of cells growing on them. In addition, the chemical nature of the surface between the produced structures, that was previously sharply limited, is of great significance for a plurality of applications in biology, optics, sensor engineering and electronics.